OCR GCSE Physics A key terms

A force exerted on the chosen system by something outside that system.

A lamp with a thin wire filament that heats up and glows when current passes through it.

A component with a resistance that is not intended to be adjusted.

A three-dimensional hand rule relating the mutually perpendicular directions of magnetic field, conventional current and force on a current-carrying conductor.

A substance that can flow; liquids and gases are fluids.

The emission of visible light by a substance after it has absorbed electromagnetic radiation, often ultraviolet radiation.

A push or pull that can change an object’s motion or shape; it is measured in newtons (N).

A graph of applied force against the resulting extension; the area beneath it represents the work done in stretching.

A force diagram showing all the external forces acting on one chosen object or system as labelled arrows.

A diagram showing all the external forces acting on one chosen object as labelled arrows.

Motion in which gravity is the only force acting on an object.

The number of complete wave cycles passing a point each second, measured in hertz (Hz).

A force that opposes relative motion between surfaces and can cause energy to be transferred by heating.

A huge collection of stars, gas and dust held together by gravity.

Electromagnetic radiation emitted during a change in an unstable or excited nucleus.

Electromagnetic radiation emitted from a nucleus, represented by $^{0}_{0}\gamma$.

Electromagnetic radiation emitted by a nucleus with excess energy.

The force exerted normally on each unit area of a surface, caused in a gas by particles colliding with that surface.

A toothed wheel that transmits rotation to another gear or a chain.

An orbit above Earth's equator that matches Earth's rotation, making a satellite appear fixed above one place on Earth.

An instrument with a metal cap, stem and thin gold leaf; movement of the leaf shows the effects of electric charge.

The change in the vertical quantity divided by the change in the horizontal quantity.

A region around matter in which another mass experiences a gravitational force.

The gravitational force acting on each kilogram of mass at a particular location, measured in newtons per kilogram (N/kg).

A non-contact pull between objects that have mass.

An attractive interaction between objects with mass.

Energy associated with an object's position in a gravitational field, measured in joules (J).